John Gill Commentary 1 Samuel 25:23

"And when Abigail saw David, she hasted, and alighted from her ass, and fell before David on her face, and bowed herself to the ground." — 1 Samuel 25:23 (ASV)

And when Abigail saw David
Whom she either knew personally, or rather supposed who he was by the number of men that followed him.

she hastened, and alighted from the ass;
on which she rode.

and fell before David on her face, and bowed herself to the ground;
in respect to, and reverence of, so great a person as David was.